Glass

The materials definition of a glass is a uniform amorphous solid material, usually produced when a suitably viscous molten material cools very rapidly to below its glass transition temperature, thereby not giving enough time for a regular crystal lattice to form. more...

A simple example is when table sugar is melted and cooled rapidly by dumping the liquid sugar onto a cold surface. The resulting solid is amorphous, not crystalline like the sugar was originally, which can be seen in its conchoidal fracture.

The word glass comes from Latin glacies (ice) and corresponds to German Glas, M.E. glas, A.S. glaes. Germanic tribes used the word glaes to describe amber, recorded by Roman historians as glaesum. Anglo-Saxons used the word glaer for amber.

The term enamel is used to describe glass fused as a decorative or functional coating on metal.

The remainder of this article will be concerned with a specific type of glass—the silica-based glasses in common use as a building, container or decorative material.

In its pure form, glass is a transparent, relatively strong, hard-wearing, essentially inert, and biologically inactive material which can be formed with very smooth and impervious surfaces. These desirable properties lead to a great many uses of glass. Glass is, however, brittle and will break into sharp shards. These properties can be modified, or even changed entirely, with the addition of other compounds or heat treatment.

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